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Annual Report 2010 published

The actual annual report of the IKP has been published and is available for download.

Apart from the "Highlights" which are also available on paper there is a multitude of individual reports which available only online.

Description of the title page image:
The most accurate method to measure the pion-nucleon scattering lengths, a+ and a−, is via measurements of the deviation of the spectra of pionic atoms from what is predicted for purely Coulombic bound states. The theoretical analysis, based on effective field theories, of each of the experiments for the energy shifts of pionic hydrogen and pionic deuterium as well as the width of pionic hydrogen gives a band in the ã+ (closely related to a+), a− plane—those bands including both theoretical as well as experimental uncertainties are shown in the figure. The ellipse shows the one σ area allowed for (ã+,a−). An update of the GMO sumrule with this improved input leads to a value of the π NN scattering length of
gc2/4π = 13.69 ± 0.12 ± 0.15 = 13.7 ± 0.2,
thus excluding values above 14 with two σ accuracy.